164 ECHINODERMATA—PELMATOZOA SUB-KINGDOM III 
fused with the top stem-joint. The posterior 6 larger than the rest, and 
truncated or excavated at its upper face. Costals three to six, decreasing in 
size upwards; the two lower ones laterally united by a few large inter- 
brachials. The posterior interray markedly different from the others ; 
composed of a large number of exceedingly minute pieces, which enclose a 
longitudinal row of six to twelve moderately small, quadrangular, anal plates, 
supporting a small tube at the upper end. Tegmen formed by small, almost 
microscopic limestone particles, and extremely flexible. Arms ten, giving 
off clusters of armlets either from the sides at intervals, or only at their 
upper ends. Middle Sub-Carboniferous ; North America and England. 
Forbesiocrinus (de Kon. and le Hon), Hall. Differs from Tazxocrinus in the 
construction of the anal area. JRA and LA both represented.  Inter- 

The 
Toa Ne 
ZUPETIY VANS 
ave Orbe. 

Fic. 270. 
Ichthyocrinus laevis, 
Conrad. Perfect 
crown. Silurian 
(Niagara Group); 
Lockport, New York 
(after Hall). 

Fic. 271. 
Lecanocrinus Bill- ae 
ingsi, Ang. Silurian; 9 bath 
Gottland. «a, Calyx, i 
seen from one side 

(right and left re- Fic, 273. 
Taxocrinus intermedius, versed); b, Crown, Taxocrinus , Meeli, Hall sp. 
W. and Sp. (after Wachis- seen from the anal Perfect crown. Sub-Carbonifer- 
muth and Springer). side (after Angelin). ous; Crawfordsville, Ind. 
brachials very numerous, arranged in some cases in twelve or more rows. 
Arms long, bifurcating, rather closely apposed, and with infolding tips. 
Sub-Carboniferous ; North America and Europe. 
Mespilocrinus, de Kon. and le Hon. Crown small and unsymmetrical, 
owing to the dextrorse arrangement of the arms. Posterior B truncated, 
and supporting a small JA, which is the only supplementary plate of the 
dorsal cup. Costals and distichals two, followed by a very few free arm- 
plates. Arms very short, closely folded, and inclining to the right, owing to 
the cuneate form of lower brachials. Sub-Carboniferous; North America 
and Europe. 
Homalocrinus, Anisocrinus, Calpiocrinus, Cyrtidocrinus, Pycnosaccus, Ang. ; 
Lithocrinus, W. and Sp. Silurian, Gottland. 
